babel-plugin-root-import with babel 7

Question

I'm trying to setup Babel 7. Never used Babel before, so i'm really starting from scratch. I've managed to install and use @babel/plugin-proposal-optional-chaining , but I'm struggling with babel-plugin-root-import .

Here is my package.json

//package.json

"scripts": {
  "start": "nodemon src/index.js --exec babel-node"
},
"devDependencies": {
  "@babel/cli": "^7.0.0-beta.51",
  "@babel/core": "^7.0.0-beta.51",
  "@babel/node": "^7.0.0-beta.51",
  "@babel/preset-env": "^7.0.0-beta.51"
},
"dependencies": {
  "@babel/plugin-proposal-optional-chaining": "^7.0.0-beta.51",
  "@babel/polyfill": "^7.0.0-beta.51",
  "babel-plugin-root-import": "^6.1.0"
}


//babel.config.js

module.exports = {
  "presets": ["@babel/preset-env"],
  "plugins": [
    ["@babel/plugin-proposal-optional-chaining"],
    ["babel-plugin-root-import",{
      "rootPathPrefix": "@"
    }]
  ]
};

Below is my code:

//src/index.js

require("./foo/index.js")();

//src/foo/index.js

module.exports = function() {
  console.log("Foo loaded")
}

When I execute the code above, I get Foo loaded in my console.

When I change src/index.js with the following:

//src/index.js

require("@/foo/index.js")();

I get the following error:

internal/modules/cjs/loader.js:596
    throw err;
    ^

Error: Cannot find module '../foo/index.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:594:15)
    at Function.Module._load (internal/modules/cjs/loader.js:520:25)
    at Module.require (internal/modules/cjs/loader.js:650:17)
    at require (internal/modules/cjs/helpers.js:20:18)
    at Object.<anonymous> (C:\Node.js\dev\babel7\src/index.js:2:1)
    at Module._compile (internal/modules/cjs/loader.js:702:30)
    at Module._compile (C:\Node.js\dev\babel7\node_modules\pirates\lib\index.js:91:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:713:10)
    at Object.newLoader [as .js] (C:\Node.js\dev\babel7\node_modules\pirates\lib\index.js:96:7)
    at Module.load (internal/modules/cjs/loader.js:612:32)
[nodemon] app crashed - waiting for file changes before starting...

If I don't set the rootPathPrefix in babel.config.js, I also cannot use the plugin with paths starting with ~, which is supposed to be the default value. What is wrong?

Many thanks!

Answer 1

If you run babel-cli directly with npx babel src/index.js just to check the output, you will find that the root import plugin is correctly changing:

require("@/foo/index.js")();

into:

require("../foo/index.js")();

@ (the project root) is correctly replaced in the index.js file inside the src folder with ..

If you want @ to refer to root/src you can set the "rootPathSuffix": "src" option. Without that option you would have to do:

require("@/src/foo/index.js")();